1.
Conservation status
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The conservation status of a group of organisms indicates whether the group still exists and how likely the group is to become extinct in the near future. Various systems of conservation status exist and are in use at international, multi-country, the IUCN Red List of Threatened Species is the best known worldwide conservation status listing and ranking system. Also included are species that have gone extinct since 500 AD, when discussing the IUCN Red List, the official term threatened is a grouping of three categories, critically endangered, endangered, and vulnerable. Widespread and abundant taxa are included in this category, Data deficient – Not enough data to make an assessment of its risk of extinction Not evaluated – Has not yet been evaluated against the criteria. The Convention on International Trade in Endangered Species of Wild Fauna and Flora aims to ensure that trade in specimens of wild animals. Many countries require CITES permits when importing plants and animals listed on CITES, in the European Union, the Birds and Habitats Directives are the legal instruments that evaluate the conservation status within the EU of species and habitats. NatureServe conservation status focuses on Latin America, United States, Canada, and it has been developed by scientists from NatureServe, The Nature Conservancy, and the network of natural heritage programs and data centers. It is increasingly integrated with the IUCN Red List system and its categories for species include, presumed extinct, possibly extinct, critically imperiled, imperiled, vulnerable, apparently secure, and secure. The system also allows ambiguous or uncertain ranks including inexact numeric ranks, NatureServe adds a qualifier for captive or cultivated only, which has a similar meaning to the IUCN Red List extinct in the wild status. The Red Data Book of the Russian Federation is used within the Russian Federation, in Australia, the Environment Protection and Biodiversity Conservation Act 1999 describes lists of threatened species, ecological communities and threatening processes. The categories resemble those of the 1994 IUCN Red List Categories & Criteria, prior to the EPBC Act, a simpler classification system was used by the Endangered Species Protection Act 1992. Some state and territory governments also have their own systems for conservation status, in Belgium, the Flemish Research Institute for Nature and Forest publishes an online set of more than 150 nature indicators in Dutch. In Canada, the Committee on the Status of Endangered Wildlife in Canada is a group of experts that assesses and designates which wild species are in danger of disappearing from Canada. Under the Species at Risk Act, it is up to the federal government, in China, the State, provinces and some counties have determined their key protected wildlife species. There is the China red data book, in Finland, a large number of species are protected under the Nature Conservation Act, and through the EU Habitats Directive and EU Birds Directive. In Germany, the Federal Agency for Nature Conservation publishes red lists of endangered species, india has the Wild Life Protection Act,1972, Amended 2003 and the Biological Diversity Act,2002. In Japan, the Ministry of Environment publishes a Threatened Wildlife of Japan Red Data Book, in the Netherlands, the Dutch Ministry of Agriculture, Nature and Food Quality publishes a list of threatened species, and conservation is enforced by the Nature Conservation Act 1998. Species are also protected through the Wild Birds and Habitats Directives, in New Zealand, the Department of Conservation publishes the New Zealand Threat Classification System lists
2.
Least Concern
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A least concern species is one which has been categorized by the International Union for Conservation of Nature as evaluated but not qualified for any other category. As such they do not qualify as threatened, near threatened, species cannot be assigned the Least Concern category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, since 2001 the category has had the abbreviation LC, following the IUCN2001 Categories & Criteria. However, around 20% of least concern taxa in the IUCN database use the code LR/lc, prior to 2001 least concern was a subcategory of the Lower Risk category and assigned the code LR/lc or. While least concern is not considered a red listed category by the IUCN, the number of animal species listed in this category totals 14033. There are also 101 animal subspecies listed and 1500 plant taxa, there are also two animal subpopulations listed, the Australasian and Southern African subpopulations of spiny dogfish. No fungi or protista have the classification, though only four species in those kingdoms have been evaluated by the IUCN, humans qualify for this category, and in 2008 were formally assessed as such by the IUCN
3.
IUCN Red List
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The IUCN Red List of Threatened Species, founded in 1964, is the worlds most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the main authority on the conservation status of species. A series of Regional Red Lists are produced by countries or organizations, the IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world, the aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. Major species assessors include BirdLife International, the Institute of Zoology, the World Conservation Monitoring Centre, collectively, assessments by these organizations and groups account for nearly half the species on the Red List. The IUCN aims to have the category of every species re-evaluated every five years if possible, the 1964 IUCN Red List of Threatened Plants used the older pre-criteria Red List assessment system. Plants listed may not, therefore, appear in the current Red List, IUCN advise that is best to check both the online Red List and the 1997 plants Red List publication. The 2006 Red List, released on 4 May 2006 evaluated 40,168 species as a whole, plus an additional 2,160 subspecies, varieties, aquatic stocks, on 12 September 2007, the World Conservation Union released the 2007 IUCN Red List of Threatened Species. Russ Mittermeier, chief of Swiss-based IUCNs Primate Specialist Group, stated that 16,306 species are endangered with extinction,188 more than in 2006, the Red List includes the Sumatran orangutan in the Critically Endangered category and the Bornean orangutan in the Endangered category. The study shows at least 1,141 of the 5,487 mammals on Earth are known to be threatened with extinction, and 836 are listed as Data Deficient. The Red List of 2012 was released 19 July 2012 at Rio+20 Earth Summit, nearly 2,000 species were added, the IUCN assessed a total of 63,837 species which revealed 19,817 are threatened with extinction. With 3,947 described as endangered and 5,766 as endangered. At threat are 41% of amphibian species, 33% of reef-building corals, 30% of conifers, 25% of mammals, the IUCN Red List has listed 132 species of plants and animals from India as Critically Endangered. Extinct – No known individuals remaining, extinct in the wild – Known only to survive in captivity, or as a naturalized population outside its historic range. Critically endangered – Extremely high risk of extinction in the wild, Endangered – High risk of extinction in the wild. Vulnerable – High risk of endangerment in the wild, near threatened – Likely to become endangered in the near future. Does not qualify for a more at-risk category, widespread and abundant taxa are included in this category. Data deficient – Not enough data to make an assessment of its risk of extinction, Not evaluated – Has not yet been evaluated against the criteria
4.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
5.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
6.
Chordate
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Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
7.
Vertebrate
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Vertebrates /ˈvɜːrtᵻbrᵻts/ comprise all species of animals within the subphylum Vertebrata /-ɑː/. Vertebrates represent the majority of the phylum Chordata, with currently about 66,000 species described. Vertebrates include the fish and the jawed vertebrates, which include the cartilaginous fish. A bony fish known as the lobe-finned fishes is included with tetrapods, which are further divided into amphibians, reptiles, mammals. Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, vertebrates make up less than five percent of all described animal species, the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, hagfish do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as Craniata when discussing morphology, molecular analysis since 1992 has suggested that hagfish are most closely related to lampreys, and so also are vertebrates in a monophyletic sense. Others consider them a group of vertebrates in the common taxon of craniata. The word origin of vertebrate derives from the Latin word vertebratus, the Proto-Indo-European language origins are still unclear. Vertebrate is derived from the vertebra, which refers to any of the bones or segments of the spinal column. All vertebrates are built along the basic body plan, a stiff rod running through the length of the animal, with a hollow tube of nervous tissue above it. In all vertebrates, the mouth is found at, or right below, the remaining part of the body continuing after the anus forms a tail with vertebrae and spinal cord, but no gut. However, a few vertebrates have secondarily lost this anatomy, retaining the notochord into adulthood, such as the sturgeon, jawed vertebrates are typified by paired appendages, but this trait is not required in order for an animal to be a vertebrate. All basal vertebrates breathe with gills, the gills are carried right behind the head, bordering the posterior margins of a series of openings from the pharynx to the exterior. Each gill is supported by a cartilagenous or bony gill arch, the bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, while the primitive jawless fish have seven. The vertebrate ancestor no doubt had more arches than this, as some of their relatives have more than 50 pairs of gills. In amphibians and some primitive fishes, the larvae bear external gills. These are reduced in adulthood, their function taken over by the gills proper in fishes, some amphibians retain the external larval gills in adulthood, the complex internal gill system as seen in fish apparently being irrevocably lost very early in the evolution of tetrapods
8.
Amphibian
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Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. They inhabit a variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, the young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a respiratory surface and some small terrestrial salamanders and frogs lack lungs. They are superficially similar to lizards but, along with mammals and birds, reptiles are amniotes, the earliest amphibians evolved in the Devonian period from sarcopterygian fish with lungs and bony-limbed fins, features that were helpful in adapting to dry land. They diversified and became dominant during the Carboniferous and Permian periods, over time, amphibians shrank in size and decreased in diversity, leaving only the modern subclass Lissamphibia. The three modern orders of amphibians are Anura, Urodela, and Apoda, the number of known amphibian species is approximately 7,000, of which nearly 90% are frogs. The smallest amphibian in the world is a frog from New Guinea with a length of just 7.7 mm. The largest living amphibian is the 1.8 m Chinese giant salamander, the study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology. The word amphibian is derived from the Ancient Greek term ἀμφίβιος, the term was initially used as a general adjective for animals that could live on land or in water, including seals and otters. Traditionally, the class Amphibia includes all tetrapod vertebrates that are not amniotes, the numbers of species cited above follows Frost and the total number of known amphibian species is over 7,000, of which nearly 90% are frogs. With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a group without unique defining features apart from shared primitive characteristics. Classification varies according to the phylogeny of the author and whether they use a stem-based or a node-based classification. The phylogeny of Paleozoic amphibians is uncertain, and Lissamphibia may possibly fall within groups, like the Temnospondyli or the Lepospondyli. If the common ancestor of amphibians and amniotes is included in Amphibia, all modern amphibians are included in the subclass Lissamphibia, which is usually considered a clade, a group of species that have evolved from a common ancestor. The three modern orders are Anura, Caudata, and Gymnophiona, although the fossils of several older proto-frogs with primitive characteristics are known, the oldest true frog is Prosalirus bitis, from the Early Jurassic Kayenta Formation of Arizona. It is anatomically similar to modern frogs. The oldest known caecilian is another Early Jurassic species, Eocaecilia micropodia, the earliest salamander is Beiyanerpeton jianpingensis from the Late Jurassic of northeastern China
9.
Frog
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A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura. The oldest fossil proto-frog appeared in the early Triassic of Madagascar, Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforests. There are approximately 4,800 recorded species, accounting for over 85% of extant amphibian species and they are also one of the five most diverse vertebrate orders. The body plan of a frog is generally characterized by a stout body, protruding eyes, cleft tongue, limbs folded underneath. Besides living in water and on dry land, the adults of some species are adapted for living underground or in trees. The skin of the frog is glandular, with secretions ranging from distasteful to toxic, Frogs skins vary in colour from well-camouflaged dappled brown, grey and green to vivid patterns of bright red or yellow and black to advertise toxicity and warn off predators. Frogs typically lay their eggs in water, the eggs hatch into aquatic larvae called tadpoles that have tails and internal gills. They have highly specialized rasping mouth parts suitable for herbivorous, omnivorous or planktivorous diets, the life cycle is completed when they metamorphose into adults. A few species deposit eggs on land or bypass the tadpole stage, adult frogs generally have a carnivorous diet consisting of small invertebrates, but omnivorous species exist and a few feed on fruit. Frogs are extremely efficient at converting what they eat into body mass and they are an important food source for predators and part of the food web dynamics of many of the worlds ecosystems. The skin is semi-permeable, making them susceptible to dehydration, so they live in moist places or have special adaptations to deal with dry habitats. Frogs are valued as food by humans and also have many roles in literature, symbolism. Frog populations have declined significantly since the 1950s, more than one third of species are considered to be threatened with extinction and over one hundred and twenty are believed to have become extinct since the 1980s. The number of malformations among frogs is on the rise and a fungal disease. Conservation biologists are working to understand the causes of these problems, the name frog derives from Old English frogga, abbreviated to frox, forsc, and frosc, probably deriving from Proto-Indo-European preu = to jump. About 88% of amphibian species are classified in the order Anura and these include around 4,810 species in 33 families, of which the Leptodactylidae, Hylidae and Ranidae are the richest in species. The use of the common frog and toad has no taxonomic justification. From a classification perspective, all members of the order Anura are frogs, there are numerous exceptions to this rule
10.
True frog
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The true frogs, family Ranidae, have the widest distribution of any frog family. They are abundant throughout most of the world, occurring on all continents except Antarctica, typically, true frogs are smooth and moist-skinned, with large, powerful legs and extensively webbed feet. The true frogs vary greatly in size, ranging from small—such as the wood frog —to the largest frog in the world, many of the true frogs are aquatic or live close to water. Most species lay their eggs in the water and go through a tadpole stage, however, as with most families of frogs, there is large variation of habitat within the family. Those of the genus Tomopterna are burrowing frogs native to Africa, there are also arboreal species of true frogs, and the family includes some of the very few amphibians that can live in brackish water. The subdivisions of the Ranidae are still a matter of dispute, most authors believe the subfamily Petropedetinae is actually a distinct family called Petropedetidae. Still, there is general agreement today that the Mantellidae, which were formerly considered another ranid subfamily, there is also a recent trend to split off the forked-tongued frogs as distinct family Dicroglossidae again. In addition, the delimitation and validity of several genera is in need of more research, namely, how the huge genus Rana is best split up requires more study. While too little of the vast diversity of frogs has been subject to recent studies to say something definite, as of mid-2008, studies are going on. Amolops has been generally delimited as a monophyletic group, odorrana and Rana plus some proposed minor genera form another group. Most of them are now treated as synonyms of the genus Hylarana. A number of taxa are placed in Ranidae incertae sedis, that is and these include, among others, Rhacophorus depressus, but this species has been given its own family. PDF fulltext Cogger, H. G. Zweifel, R. G, kirschner, D. Encyclopedia of Reptiles & Amphibians. ISBN 1-877019-69-0 Frost, Darrel R. Amphibian Species of the World Version 3 - Petropedetidae Noble,1931, American Museum of Natural History, New York, USA. Bulletin of the American Museum of Natural History, gordon, Malcolm S. Schmidt-Nielsen, Knut, Kelly, Hamilton M. Osmotic Regulation in the Crab-Eating Frog. Constraints in naming parts of the Tree of Life, phylogeny of the New World true frogs. Hillis, David M. Cannatella, David C, taxonomic freedom and the role of official lists of species names. Specchio delle Scienze, o, Giornale Enciclopedico di Sicilia 2, doi,10. 1016/j. ympev.2007.09.016 PDF fulltext Amphibian and Frogs of Peninsular Malaysia - Family Ranidae
11.
Binomial nomenclature
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Such a name is called a binomial name, a binomen, binominal name or a scientific name, more informally it is also called a Latin name. The first part of the name identifies the genus to which the species belongs, for example, humans belong to the genus Homo and within this genus to the species Homo sapiens. The formal introduction of system of naming species is credited to Carl Linnaeus. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus. Although the general principles underlying binomial nomenclature are common to these two codes, there are differences, both in the terminology they use and in their precise rules. Similarly, both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a name is usually given, at least when it is first mentioned. In zoology Patella vulgata Linnaeus,1758, the original name given by Linnaeus was Fringilla domestica, the parentheses indicate that the species is now considered to belong in a different genus. The ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, in botany Amaranthus retroflexus L. – L. is the standard abbreviation used in botany for Linnaeus. – Linnaeus first named this bluebell species Scilla italica, Rothmaler transferred it to the genus Hyacinthoides, the ICN does not require that the dates of either publication be specified. Prior to the adoption of the binomial system of naming species. Together they formed a system of polynomial nomenclature and these names had two separate functions. First, to designate or label the species, and second, to be a diagnosis or description, such polynomial names may sometimes look like binomials, but are significantly different. For example, Gerards herbal describes various kinds of spiderwort, The first is called Phalangium ramosum, Branched Spiderwort, is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia. The Latin phrases are short descriptions, rather than identifying labels, the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné. It was in his 1753 Species Plantarum that he first began using a one-word trivial name together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as an epithet or specific name
12.
Johann Christian Daniel von Schreber
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Johann Christian Daniel von Schreber, often styled J. C. D. von Schreber, was a German naturalist. He was appointed professor of materia medica at the University of Erlangen in 1769, in 1774 he began writing a multi-volume set of books entitled Die Säugethiere in Abbildungen nach der Natur mit Beschreibungen, which focused on the mammals of the world. Many of the animals included were given a name for the first time. From 1791 until his death in 1810, he was the President of the German Academy of Sciences Leopoldina and he was elected a member of the Royal Swedish Academy of Sciences in 1787. In April 1795 he was elected a Fellow of the Royal Society Numerous honors were bestowed on him including the office of a count palatine. Schreber also wrote on entomology notably Schreberi Novae Species Insectorvm and his herbarium collection has been preserved in the Botanische Staatssammlung München since 1813
13.
Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
14.
Leopard frog
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A leopard frog can mean any frog of about 14 species within the true frog genus Lithobates. They are generally similarly colored—green with prominent black spotting that sometimes appears as a leopard pattern and they are distinguished by their distribution and certain rather subtle ecological, behavioral, morphological and genetic traits. Their range in the North-American subcontinent extends throughout temperate and subtropical North America to northern Mexico and they are also found in Europe. Leopard frogs were briefly grouped with the American bullfrog and relatives in the genus Lithobates and this species has now been identified as far south as southeastern Virginia and northeastern North Carolina. On 30 October 2014, it was announced that the frog which was found in March 2012, is a new species of leopard frog called Rana kauffeldi that once inhabited Manhattan, New York. Hillis, David M. & Wilcox, Thomas P. Phylogeny of the New World true frogs Mol, doi,10. 1016/j. ympev.2004.10.007 PMID15619443 PDF fulltext Hillis, David. M. Constraints in naming parts of the Tree of Life, doi,10. 1016/j. ympev.2006.08.001 PMID16997582 PDF fulltext Leopard Frog at Western Ecological Research Centre Plains Leopard Frog – Rana blairi at the Iowa Reptile and Amphibian Field Guide
15.
Family (biology)
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In biological classification, family is one of the eight major taxonomic ranks, it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks above the rank of genus. In vernacular usage, a family may be named one of its common members, for example, walnuts and hickory trees belong to the family Juglandaceae. What does or does not belong to a family—or whether a family should be recognized at all—are proposed and determined by practicing taxonomists. There are no rules for describing or recognizing a family. Taxonomists often take different positions about descriptions of taxa, and there may be no broad consensus across the community for some time. Some described taxa are accepted broadly and quickly, but others only rarely, if at all, the naming of families is codified by various international codes. In zoological nomenclature, the names of animals end with the suffix -idae. The concept of rank at time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera. Carolus Linnaeus used the word familia in his Philosophia botanica to denote groups of plants, trees, herbs, ferns, palms. He used this term only in the section of the book. In zoology, the family as an intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes. He used families in some but not in all his orders of insects, families can be used for evolutionary, palaeontological and generic studies because they are more stable than lower taxonomic levels such as genera and species
16.
Canada
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Canada is a country in the northern half of North America. Canadas border with the United States is the worlds longest binational land border, the majority of the country has a cold or severely cold winter climate, but southerly areas are warm in summer. Canada is sparsely populated, the majority of its territory being dominated by forest and tundra. It is highly urbanized with 82 per cent of the 35.15 million people concentrated in large and medium-sized cities, One third of the population lives in the three largest cities, Toronto, Montreal and Vancouver. Its capital is Ottawa, and other urban areas include Calgary, Edmonton, Quebec City, Winnipeg. Various aboriginal peoples had inhabited what is now Canada for thousands of years prior to European colonization. Pursuant to the British North America Act, on July 1,1867, the colonies of Canada, New Brunswick and this began an accretion of provinces and territories to the mostly self-governing Dominion to the present ten provinces and three territories forming modern Canada. With the Constitution Act 1982, Canada took over authority, removing the last remaining ties of legal dependence on the Parliament of the United Kingdom. Canada is a parliamentary democracy and a constitutional monarchy, with Queen Elizabeth II being the head of state. The country is officially bilingual at the federal level and it is one of the worlds most ethnically diverse and multicultural nations, the product of large-scale immigration from many other countries. Its advanced economy is the eleventh largest in the world, relying chiefly upon its abundant natural resources, Canadas long and complex relationship with the United States has had a significant impact on its economy and culture. Canada is a country and has the tenth highest nominal per capita income globally as well as the ninth highest ranking in the Human Development Index. It ranks among the highest in international measurements of government transparency, civil liberties, quality of life, economic freedom, Canada is an influential nation in the world, primarily due to its inclusive values, years of prosperity and stability, stable economy, and efficient military. While a variety of theories have been postulated for the origins of Canada. In 1535, indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to the village of Stadacona, from the 16th to the early 18th century Canada referred to the part of New France that lay along the St. Lawrence River. In 1791, the area became two British colonies called Upper Canada and Lower Canada collectively named The Canadas, until their union as the British Province of Canada in 1841. Upon Confederation in 1867, Canada was adopted as the name for the new country at the London Conference. The transition away from the use of Dominion was formally reflected in 1982 with the passage of the Canada Act, later that year, the name of national holiday was changed from Dominion Day to Canada Day
17.
United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
18.
Minnesota
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Minnesota is a state in the midwestern and northern regions of the United States. Minnesota was admitted as the 32nd U. S. state on May 11,1858, the state has a large number of lakes, and is known by the slogan Land of 10,000 Lakes. Its official motto is LÉtoile du Nord, Minnesota is the 12th largest in area and the 21st most populous of the U. S. Minnesota is known for its progressive political orientation and its high rate of civic participation and voter turnout. Until European settlement, Minnesota was inhabited by the Dakota and Ojibwe/Anishinaabe, in recent decades, immigration from Asia, the Horn of Africa, and Latin America has broadened its historic demographic and cultural composition. Minnesotas standard of living index is among the highest in the United States, Native Americans demonstrated the name to early settlers by dropping milk into water and calling it mnisota. Many places in the state have similar names, such as Minnehaha Falls, Minneiska, Minneota, Minnetonka, Minnetrista, and Minneapolis, a combination of mni and polis, Minnesota is the second northernmost U. S. state. Its isolated Northwest Angle in Lake of the Woods county is the part of the 48 contiguous states lying north of the 49th parallel. The state is part of the U. S. region known as the Upper Midwest and it shares a Lake Superior water border with Michigan and a land and water border with Wisconsin to the east. Iowa is to the south, North Dakota and South Dakota are to the west, with 86,943 square miles, or approximately 2.25 percent of the United States, Minnesota is the 12th-largest state. Minnesota has some of the Earths oldest rocks, gneisses that are about 3.6 billion years old. About 2.7 billion years ago, basaltic lava poured out of cracks in the floor of the primordial ocean, the roots of these volcanic mountains and the action of Precambrian seas formed the Iron Range of northern Minnesota. Following a period of volcanism 1, in more recent times, massive ice sheets at least one kilometer thick ravaged the landscape of the state and sculpted its terrain. The Wisconsin glaciation left 12,000 years ago and these glaciers covered all of Minnesota except the far southeast, an area characterized by steep hills and streams that cut into the bedrock. This area is known as the Driftless Zone for its absence of glacial drift, much of the remainder of the state outside the northeast has 50 feet or more of glacial till left behind as the last glaciers retreated. Gigantic Lake Agassiz formed in the northwest 13,000 years ago and its bed created the fertile Red River valley, and its outflow, glacial River Warren, carved the valley of the Minnesota River and the Upper Mississippi downstream from Fort Snelling. Minnesota is geologically quiet today, it experiences earthquakes infrequently, the states high point is Eagle Mountain at 2,301 feet, which is only 13 miles away from the low of 601 feet at the shore of Lake Superior. Notwithstanding dramatic local differences in elevation, much of the state is a rolling peneplain. Two major drainage divides meet in Minnesotas northeast in rural Hibbing, forming a triple watershed, precipitation can follow the Mississippi River south to the Gulf of Mexico, the Saint Lawrence Seaway east to the Atlantic Ocean, or the Hudson Bay watershed to the Arctic Ocean
19.
Vermont
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Vermont is a state in the New England region of the northeastern United States. It borders the other U. S. states of Massachusetts to the south, New Hampshire to the east, New York to the west, and the Canadian province of Quebec to the north. Lake Champlain forms half of Vermonts western border with the state of New York, Vermont is the 2nd-least populous of the U. S. states, with nearly 50,000 more residents than Wyoming. The capital is Montpelier, the least populous state capital in the U. S, the most populous municipality, Burlington, is the least populous city in the U. S. to be the most populous within a state. As of 2015, Vermont continued to be the producer of maple syrup in the U. S. It was ranked as the safest state in the country in January 2016, for thousands of years inhabited by indigenous peoples, including the Algonquian-speaking Abenaki and Mohawk, much of the territory that is now Vermont was claimed by Frances colony of New France. France ceded the territory to Great Britain after being defeated in 1763 in the Seven Years War, for many years, the nearby colonies, especially the provinces of New Hampshire and New York, disputed control of the area. Settlers who held land titles granted by New York were opposed by the Green Mountain Boys militia, ultimately, those settlers prevailed in creating an independent state, the Vermont Republic. Founded in 1777 during the American Revolutionary War, the republic lasted for 14 years, aside from the original 13 states that were formerly colonies, Vermont is one of only four U. S. states that were previously sovereign states. Vermont was also the first state to join the U. S. as its 14th member state after the original 13, while still an independent republic, Vermont was the first of any future U. S. state to partially abolish slavery. It played an important geographic role in the Underground Railroad, sights in Vermont Vermont is located in the New England region of the northeastern United States and comprises 9,614 square miles, making it the 45th-largest state. It is the state that does not have any buildings taller than 124 feet. Land comprises 9,250 square miles and water comprises 365 square miles, making it the 43rd-largest in land area, in total area, it is larger than El Salvador and smaller than Haiti. The west bank of the Connecticut River marks the eastern border with New Hampshire. 41% of Vermonts land area is part of the Connecticut Rivers watershed, Lake Champlain, the major lake in Vermont, is the sixth-largest body of fresh water in the United States and separates Vermont from New York in the northwest portion of the state. From north to south, Vermont is 159 miles long and its greatest width, from east to west, is 89 miles at the Canada–U. S. Border, the narrowest width is 37 miles at the Massachusetts line, the states geographic center is approximately three miles east of Roxbury, in Washington County. There are fifteen U. S. federal border crossings between Vermont and Canada, the origin of the name Vermont is uncertain, but likely comes from the French les Verts Monts, meaning the Green Mountains
20.
Anatomical terms of location
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Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. All vertebrates have the basic body plan – they are strictly bilaterally symmetrical in early embryonic stages. That is, they have left and right halves if divided down the centre. For these reasons, the directional terms can be considered to be those used in vertebrates. By extension, the terms are used for many other organisms as well. While these terms are standardized within specific fields of biology, there are unavoidable, sometimes dramatic, for example, differences in terminology remain a problem that, to some extent, still separates the terminology of human anatomy from that used in the study of various other zoological categories. The vertebrates and Craniata share a heritage and common structure. To avoid ambiguities this terminology is based on the anatomy of each animal in a standard way, for humans, one type of vertebrate, anatomical terms may differ from other forms of vertebrates. Thus what is on top of a human is the head, whereas the top of a dog may be its back, for example, many species are not even bilaterally symmetrical. In these species, terminology depends on their type of symmetry, all descriptions are with respect to the organism in its standard anatomical position, even when the organism in question has appendages in another position. This helps avoid confusion in terminology when referring to the organism in different postures. In humans, this refers to the body in a position with arms at the side. While the universal vertebrate terminology used in medicine would work in human medicine. Many anatomical terms can be combined, either to indicate a position in two axes simultaneously or to indicate the direction of a movement relative to the body, for example, anterolateral indicates a position that is both anterior and lateral to the body axis. There is no limit to the contexts in which terms may be modified to qualify each other in such combinations. Generally the modifier term is truncated and an o or an i is added in prefixing it to the qualified term, where desirable three or more terms may be agglutinated or concatenated, as in anteriodorsolateral. Such terms sometimes used to be hyphenated, but the tendency is to omit the hyphen. There is however little basis for any rule to interfere with choice of convenience in such usage
21.
Tympanum (anatomy)
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The tympanum is an external hearing structure in animals such as mammals, birds, some reptiles, some amphibians and some insects. In general, any animal that reacts to sounds or communicates by means of sound and this typically consists of a membrane capable of vibration known as the tympanum, an air-filled chamber and sensory organs to detect the auditory stimuli. In frogs and toads, the tympanum is a large oval shape membrane made up of nonglandular skin. It is located just behind the eye and it does not process sound waves, it simply transmits them to the inner parts of the amphibians ear, which is protected from the entry of water and other foreign objects. A frog’s ear drum works in much the same way as does a human ear drum. It is a membrane that is stretched across a ring of cartilage like a drum that vibrates. Crossing the middle ear chamber there is a called the columella that is connected to the tympanum, and another ossicle, the operculum. A frogs lungs are involved in the reception of sound. Frog Eardrum Tympanal organ in insects
22.
Tadpole
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A tadpole is the larval stage in the life cycle of an amphibian, particularly that of a frog or toad. They are usually wholly aquatic, though some species have tadpoles that are terrestrial, when first hatched from the egg they have a more or less globular body, a laterally compressed tail and internal or external gills. As they grow they undergo metamorphosis, during which process they grow limbs, develop lungs, most tadpoles are herbivorous and during metamorphosis the mouth and internal organs are rearranged to prepare for an adult carnivorous lifestyle. Having no hard parts, it might be expected that fossil tadpoles would not exist, however, traces of biofilms have been preserved and fossil tadpoles have been found dating back to the Miocene. Tadpoles are eaten in parts of the world and are mentioned in folk tales. The name tadpole is from Middle English taddepol, made up of the elements tadde, toad, similarly, pollywog / polliwog is from Middle English polwygle, made up of the same pol, head, and wiglen, to wiggle. Tadpoles are young amphibians that live in the water, though a few tadpoles are semi-terrestrial and terrestrial. During the tadpole stage of the life cycle, most respire by means of autonomous external or internal gills. They do not usually have arms or legs until the transition to adulthood, as a tadpole matures, it most commonly metamorphosizes by gradually growing limbs and then outwardly absorbing its tail by apoptosis. Lungs develop around the time of leg development, and tadpoles late in development will often be found near the surface of the water, where they breathe air. During the final stages of external metamorphosis, the mouth changes from a small. The intestines shorten to accommodate the new diet, most tadpoles are herbivorous, subsisting on algae and plants. Some species are omnivorous, eating detritus and, when available, tadpoles vary greatly in size, both during their development and between species. For example, in a family, Megophryidae, length of late-stage tadpoles varies between 33 millimetres and 106 millimetres. The tadpoles of Pseudis paradoxa grow to 25 centimetres, the largest of any frog, despite their soft-bodied nature and lack of mineralised hard parts, fossil tadpoles have been recovered from Upper Miocene strata. They are preserved by virtue of biofilms, with more robust structures preserved as a carbon film, in Miocene fossils from Libros, Spain, the brain case is preserved in calcium carbonate, and the nerve cord in calcium phosphate. Other parts of the tadpoles bodies exist as organic remains and bacterial biofilms, tadpole remains with telltale external gills are also known from several of the Labyrinthodont groups. Some tadpoles are used as food, tadpoles of megophryid frog Oreolalax rhodostigmatus are particularly large, more than 10 cm in length, and are collected for human consumption in China
23.
Welland Canal
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The Welland Canal is a ship canal in Ontario, Canada, connecting Lake Ontario and Lake Erie. It forms a key section of the St. Lawrence Seaway, traversing the Niagara Peninsula from Port Weller to Port Colborne, it enables ships to ascend and descend the Niagara Escarpment and bypass Niagara Falls. Approximately 40,000,000 tonnes of cargo are carried through the canal annually by about 3,000 ocean and it was a major factor in the growth of the city of Toronto. The Welland Canal eclipsed other, narrower canals in the region, such as the Trent-Severn Waterway and, significantly, the southern, Lake Erie terminus of the canal is 99.5 metres higher than the northern terminus on Lake Ontario. The canal includes eight 24. 4-metre-wide ship locks, seven of the locks are 233.5 m long and raise passing ships by between 13 and 15 m each. The southernmost lock, is 349.9 m in length, the Garden City Skyway passes over the canal, restricting the maximum height of the masts of the ships allowed on this canal to 35.5 m. All other highway or railroad crossings of the Welland Canal are either movable bridges or subterranean tunnels, the maximum permissible length of a ship in this canal is 225.5 metres. It takes ships an average of eleven hours to traverse the entire length of the Welland Canal. The Welland Canal Company was incorporated by the Province of Upper Canada, in 1824, One of the petitioners was William Hamilton Merritt, who was in part looking to provide a regular flow of water for his watermills. The construction began at Allanburg, Ontario, on November 30 and this canal opened for a trial run on November 30,1829. After a short ceremony at Lock One, in Port Dalhousie, the first canal ran from Port Dalhousie, Ontario on Lake Ontario south along Twelve Mile Creek to St. Catharines. From there it took a route up the Niagara Escarpment through Merritton, Ontario to Thorold. Ships went east on the Welland River to Chippawa, at the end of the old portage road. Originally, the section between Allanburg and Port Robinson was planned to be carried in a subterranean tunnel, however, the sandy soil in this part of Ontario made a tunnel infeasible, and a deep open-cut canal was dug instead. A southern extension from Port Robinson opened in 1833, with the founding of Port Colborne and this extension followed the Welland River south to Welland, and then split to run south to Port Colborne on Lake Erie. A feeder canal ran southwest from Welland to another point on Lake Erie, with the opening of the extension, the canal stretched 44 km between the two lakes, with 40 wooden locks. The minimum lock size was 33.5 by 6.7 m, deterioration of the wood used in the 40 locks and the increasing size of ships led to demand for the Second Welland Canal, which used cut stone locks, within just a few years. The public buyout was completed in 1841, and work began to deepen the canal and to reduce the number of locks to 27, each 45.7 by 8.1 m
24.
Ontario
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Ontario, one of the 13 provinces and territories of Canada, is located in east-central Canada. It is Canadas most populous province by a margin, accounting for nearly 40 percent of all Canadians. Ontario is fourth-largest in total area when the territories of the Northwest Territories and it is home to the nations capital city, Ottawa, and the nations most populous city, Toronto. There is only about 1 km of land made up of portages including Height of Land Portage on the Minnesota border. Ontario is sometimes divided into two regions, Northern Ontario and Southern Ontario. The great majority of Ontarios population and arable land is located in the south, in contrast, the larger, northern part of Ontario is sparsely populated with cold winters and is heavily forested. The province is named after Lake Ontario, a thought to be derived from Ontarí, io, a Huron word meaning great lake, or possibly skanadario. Ontario has about 250,000 freshwater lakes, the province consists of three main geographical regions, The thinly populated Canadian Shield in the northwestern and central portions, which comprises over half the land area of Ontario. Although this area mostly does not support agriculture, it is rich in minerals and in part covered by the Central and Midwestern Canadian Shield forests, studded with lakes, Northern Ontario is subdivided into two sub-regions, Northwestern Ontario and Northeastern Ontario. The virtually unpopulated Hudson Bay Lowlands in the north and northeast, mainly swampy. Southern Ontario which is further sub-divided into four regions, Central Ontario, Eastern Ontario, Golden Horseshoe, the highest point is Ishpatina Ridge at 693 metres above sea level located in Temagami, Northeastern Ontario. In the south, elevations of over 500 m are surpassed near Collingwood, above the Blue Mountains in the Dundalk Highlands, the Carolinian forest zone covers most of the southwestern region of the province. A well-known geographic feature is Niagara Falls, part of the Niagara Escarpment, the Saint Lawrence Seaway allows navigation to and from the Atlantic Ocean as far inland as Thunder Bay in Northwestern Ontario. Northern Ontario occupies roughly 87 percent of the area of the province. Point Pelee is a peninsula of Lake Erie in southwestern Ontario that is the southernmost extent of Canadas mainland, Pelee Island and Middle Island in Lake Erie extend slightly farther. All are south of 42°N – slightly farther south than the border of California. The climate of Ontario varies by season and location, the effects of these major air masses on temperature and precipitation depend mainly on latitude, proximity to major bodies of water and to a small extent, terrain relief. In general, most of Ontarios climate is classified as humid continental, Ontario has three main climatic regions
25.
Snake
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Snakes are elongated, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales, many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their bodies, snakes paired organs appear one in front of the other instead of side by side. Some species retain a pelvic girdle with a pair of claws on either side of the cloaca. Additionally, sea snakes are widespread throughout the Indian and Pacific Oceans, more than 20 families are currently recognized, comprising about 500 genera and about 3,400 species. They range in size from the tiny,10.4 cm -long thread snake to the reticulated python of 6.95 meters in length, the fossil species Titanoboa cerrejonensis was 12.8 meters long. Snakes are thought to have evolved from either burrowing or aquatic lizards, perhaps during the Jurassic period, the diversity of modern snakes appeared during the Paleocene period. The oldest preserved descriptions of snakes can be found in the Brooklyn Papyrus, most species are nonvenomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause injury or death to humans. Nonvenomous snakes either swallow prey alive or kill by constriction, the word ousted adder, as adder went on to narrow in meaning, though in Old English næddre was the general word for snake. The other term, serpent, is from French, ultimately from Indo-European *serp-, the fossil record of snakes is relatively poor because snake skeletons are typically small and fragile making fossilization uncommon. Fossils readily identifiable as snakes first appear in the record during the Cretaceous period. The earliest known snake fossils come from the marine simoliophiids. Based on comparative anatomy, there is consensus that snakes descended from lizards, pythons and boas—primitive groups among modern snakes—have vestigial hind limbs, tiny, clawed digits known as anal spurs, which are used to grasp during mating. The families Leptotyphlopidae and Typhlopidae also possess remnants of the pelvic girdle, front limbs are nonexistent in all known snakes. This is caused by the evolution of Hox genes, controlling limb morphogenesis, the axial skeleton of the snakes’ common ancestor, like most other tetrapods, had regional specializations consisting of cervical, thoracic, lumbar, sacral, and caudal vertebrae. Early in snake evolution, the Hox gene expression in the axial skeleton responsible for the development of the thorax became dominant, as a result, the vertebrae anterior to the hindlimb buds all have the same thoracic-like identity. In other words, most of a skeleton is an extremely extended thorax
26.
Raccoon
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The raccoon, sometimes spelled racoon, also known as the common raccoon, North American raccoon, northern raccoon and colloquially as coon, is a medium-sized mammal native to North America. The raccoon is the largest of the family, having a body length of 40 to 70 cm. Its grayish coat mostly consists of dense underfur which insulates it against cold weather, two of the raccoons most distinctive features are its extremely dexterous front paws and its facial mask, which are themes in the mythology of several Native American ethnic groups. Raccoons are noted for their intelligence, with studies showing that they are able to remember the solution to tasks for up to three years, the diet of the omnivorous raccoon, which is usually nocturnal, consists of about 40% invertebrates, 33% plant foods, and 27% vertebrates. As a result of escapes and deliberate introductions in the century, raccoons are now also distributed across mainland Europe, Caucasia. Though previously thought to be solitary, there is now evidence that raccoons engage in social behavior. Home range sizes vary anywhere from 3 hectares for females in cities to 5,000 hectares for males in prairies, after a gestation period of about 65 days, two to five young, known as kits, are born in spring. The kits are subsequently raised by their mother until dispersal in late fall, although captive raccoons have been known to live over 20 years, their life expectancy in the wild is only 1.8 to 3.1 years. In many areas, hunting and vehicular injury are the two most common causes of death, the word raccoon was adopted into English from the native Powhatan term, as used in the Virginia Colony. It was recorded on Captain John Smiths list of Powhatan words as aroughcun and it has also been identified as a Proto-Algonquian root *ahrah-koon-em, meaning one who rubs, scrubs and scratches with its hands. Similarly, Spanish colonists adopted the Spanish word mapache from the Nahuatl mapachitli of the Aztecs, in French and European Portuguese, the washing behavior is combined with these languages term for rat, yielding, respectively, raton laveur and ratão-lavadeiro. The colloquial abbreviation coon is used in words like coonskin for fur clothing and in phrases like old coon as a self-designation of trappers. In the 1830s, the U. S. Whig Party used the raccoon as an emblem, causing them to be known as coons by their political opponents. Soon after that it became an ethnic slur, especially in use between 1880 and 1920, and the term is considered offensive. In 1780, Gottlieb Conrad Christian Storr placed the raccoon in its own genus Procyon and it is also possible that Storr had its nocturnal lifestyle in mind and chose the star Procyon as eponym for the species. Based on fossil evidence from France and Germany, the first known members of the family Procyonidae lived in Europe in the late Oligocene about 25 million years ago. Similar tooth and skull structures suggest procyonids and weasels share a common ancestor, after the then-existing species crossed the Bering Strait at least six million years later in the early Miocene, the center of its distribution was probably in Central America. Coatis and raccoons have been considered to share common descent from a species in the genus Paranasua present between 5.2 and 6.0 million years ago
27.
Human
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Modern humans are the only extant members of Hominina tribe, a branch of the tribe Hominini belonging to the family of great apes. Several of these hominins used fire, occupied much of Eurasia and they began to exhibit evidence of behavioral modernity around 50,000 years ago. In several waves of migration, anatomically modern humans ventured out of Africa, the spread of humans and their large and increasing population has had a profound impact on large areas of the environment and millions of native species worldwide. Humans are uniquely adept at utilizing systems of communication for self-expression and the exchange of ideas. Humans create complex structures composed of many cooperating and competing groups, from families. Social interactions between humans have established a wide variety of values, social norms, and rituals. These human societies subsequently expanded in size, establishing various forms of government, religion, today the global human population is estimated by the United Nations to be near 7.5 billion. In common usage, the word generally refers to the only extant species of the genus Homo—anatomically and behaviorally modern Homo sapiens. In scientific terms, the meanings of hominid and hominin have changed during the recent decades with advances in the discovery, there is also a distinction between anatomically modern humans and Archaic Homo sapiens, the earliest fossil members of the species. The English adjective human is a Middle English loanword from Old French humain, ultimately from Latin hūmānus, the words use as a noun dates to the 16th century. The native English term man can refer to the species generally, the species binomial Homo sapiens was coined by Carl Linnaeus in his 18th century work Systema Naturae. The generic name Homo is a learned 18th century derivation from Latin homō man, the species-name sapiens means wise or sapient. Note that the Latin word homo refers to humans of either gender, the genus Homo evolved and diverged from other hominins in Africa, after the human clade split from the chimpanzee lineage of the hominids branch of the primates. The closest living relatives of humans are chimpanzees and gorillas, with the sequencing of both the human and chimpanzee genome, current estimates of similarity between human and chimpanzee DNA sequences range between 95% and 99%. The gibbons and orangutans were the first groups to split from the leading to the humans. The splitting date between human and chimpanzee lineages is placed around 4–8 million years ago during the late Miocene epoch, during this split, chromosome 2 was formed from two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. There is little evidence for the divergence of the gorilla, chimpanzee. Each of these species has been argued to be an ancestor of later hominins
28.
Bat
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Bats are mammals of the order Chiroptera whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, Bats do not flap their entire forelimbs, as birds do, but instead flap their spread-out digits, which are very long and covered with a thin membrane or patagium. About 70% of bat species are insectivores, most of the rest are frugivores, or fruit eaters. A few species, such as the bat, feed from animals other than insects, with the vampire bats being hematophagous. Bats are present throughout most of the world, with the exception of cold regions. They perform the vital roles of pollinating flowers and dispersing fruit seeds. Bats are economically important, as they consume insect pests, reducing the need for pesticides, the smallest bat is the Kittis hog-nosed bat, measuring 29–34 mm in length,15 cm across the wings and 2–2.6 g in mass. It is also arguably the smallest extant species of mammal, with the Etruscan shrew being the other contender. The largest species of bat are a few species of Pteropus, the Mexican free-tailed bat is the fastest flying animal in horizontal flight. An older English name for bats is flittermouse, which matches their name in other Germanic languages, middle English had bakke, most likely cognate with Old Swedish natbakka, which may have undergone a shift from -k- to -t- influenced by Latin blatta, moth, nocturnal insect. They were formerly grouped in the superorder Archonta, along with the treeshrews, colugos, genetic studies have now placed bats in the superorder Laurasiatheria, along with carnivorans, pangolins, odd-toed ungulates, even-toed ungulates, and cetaceans. A recent study by Zhang et al. places Chiroptera as a taxon to the clade Perissodactyla. The phylogenetic relationships of the different groups of bats have been the subject of much debate and this hypothesis recognized differences between microbats and megabats and acknowledged that flight has only evolved once in mammals. Most molecular biological evidence supports the view that bats form a single or monophyletic group, in the 1980s, a hypothesis based on morphological evidence was offered that stated the Megachiroptera evolved flight separately from the Microchiroptera. The so-called flying primate hypothesis proposes that, when adaptations to flight are removed, one example is that the brains of megabats show a number of advanced characteristics that link them to primates. Although recent genetic studies support the monophyly of bats, debate continues as to the meaning of available genetic. Genetic evidence indicates that megabats originated during the early Eocene and should be placed within the four lines of microbats. Consequently, two new suborders based on molecular data have been proposed and these two new suborders are strongly supported by statistical tests
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Pickerel frog
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The pickerel frog is a small North American frog, characterized by the appearance of seemingly hand-drawn squares on its dorsal surface. The pickerel frog is a medium sized gray or tan frog marked with seven to twenty-one irregular rectangular dark brown spots which are oriented in two columns down its back, the distinctive rectangular spots of the pickerel frog may blend together to form a long rectangle along the back. All leopard frogs have circular spots, in addition, pickerel frogs have prominent dorsolateral ridges that are unbroken. Another important distinguishing mark is the orange or yellow flash pattern found on the surface of the hind legs of pickerel frogs. The frog must be picked up to examine this, as the cover the coloration otherwise. The plains leopard frog exhibits this coloration as well, but the ridges are interrupted. The front toes of pickerel frogs are not webbed, a characteristic for some frogs of the genus Rana. This allows pickerel frogs to be fit for terrestrial life, Pickerel frogs display sexual dimorphism, the females are typically larger and darker in color than the males. During the summer and breeding males can be recognized by their swollen thumbs. Males also have vocal sacs located between the tympanum and the foreleg. In general, secondary sexual characteristic are not typically evident outside of the season, therefore. The pickerel frog ranges in the west from much of Wisconsin, southeast Minnesota, eastern Iowa, through Missouri, to the east they extend through northern Louisiana, most of Mississippi, northern Alabama, Georgia, and South Carolina to the coast. Their northern range extends into Canada in the reaches of Ontario, Quebec, New Brunswick. The range is spotty through the states and a field guide should be obtained for the specifics on ranges in a particular area. Pickerel frogs have varied habitats, the northern specimen prefers to live near cold and they prefer rocky ravines, bogs and meadow streams, but can be found around lakes and rivers that are heavily wooded. The southern specimen prefer warmer waters, like those of the Coastal Plain and floodplain swamps and they are seen most often along the edges of streams, lakes, rivers, and even flooded ditches. During the winter months they will hibernate under the silt and debris in their aquatic environments, Pickerel frogs prefer cool clear water. They breed in temporary ponds and permanent ponds but appear to favor ponds with long to permanent hydroperiods
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Southern leopard frog
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The southern leopard frog is a species of true frog. It is native to the eastern United States from Kansas to New York to Florida and it is also an introduced species in some areas. This frog is up to 13 centimeters long and it is green or brown in color with a yellowish ridge along each side of the back. There are rounded dark spots on the back and sides, there is a light spot on each eardrum. The male has larger forelimbs than the female, the breeding male has vocal sacs that are spherical when inflated. The call is described as a trill, chuckling croak. The larva is mottled, and the eyes are positioned on the top of the head and it grows to 7.6 centimeters in length before maturing. The female lays an egg mass that is baseball-sized when close to hatching time and this frog lives in many types of shallow freshwater habitat and sometimes slightly brackish water. It is usually close to water but it can stay on dry land for long periods of time. During warmer months it moves away from the water for most of the time and it is mostly nocturnal, but it can be active during the day and the night, especially during rainfall. It breeds in the winter and spring, and sometimes in the fall, the egg mass is connected to aquatic vegetation. Eggs hatch in 4 days to two weeks. The tadpoles take 50 to 75 days to develop to adulthood, in northern parts of its range it is dormant during the winter months, during which time it remains in well-oxygenated, unfrozen water bodies. This frog is widespread across the eastern United States, especially the southeast and it is the most common frog in Florida and in several other regions. It is a species in the Bahamas. There was also a population in Southern California at Prado Flood Control Basin that has disappeared. Proceedings of the American Philosophical Society, Systematics of the Rana pipiens Complex, Puzzle and Paradigm. Annual Review of Ecology and Systematics, hillis, D. M. Constraints in naming parts of the Tree of Life
31.
Ribonuclease
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Ribonuclease is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within the EC2.7 and 3.1 classes of enzymes, all organisms studied contain many RNases of many different classes, showing that RNA degradation is a very ancient and important process. In addition, active RNA degradation systems are a first defense against RNA viruses, some cells also secrete copious quantities of non-specific RNases such as A and T1. RNases are, therefore, extremely common, resulting in very short lifespans for any RNA that is not in a protected environment. It is worth noting that all intracellular RNAs are protected from RNase activity by a number of strategies including 5 end capping,3 end polyadenylation, RI is used in most laboratories that study RNA to protect their samples against degradation from environmental RNases. RNases play a role in many biological processes, including angiogenesis. Many stress-response toxins of prokaryotic toxin-antitoxin systems have shown to have RNase activity. EC3.1.27.5, RNase A is an RNase that is used in research. RNase A is one of the hardiest enzymes in common laboratory usage and it is specific for single-stranded RNAs. It cleaves the 3-end of unpaired C and U residues, ultimately forming a 3-phosphorylated product via a 2, 3-cyclic monophosphate intermediate. It does not require any cofactors for its activity EC3.1.26.4, RNase H is a non-specific endonuclease and catalyzes the cleavage of RNA via a hydrolytic mechanism, aided by an enzyme-bound divalent metal ion. RNase H leaves a 5-phosphorylated product, EC3.1.26.3, RNase III is a type of ribonuclease that cleaves rRNA from transcribed polycistronic RNA operon in prokaryotes. Its function is to cleave off an extra, or precursor, RNase P is one of two known multiple turnover ribozymes in nature. A form of RNase P that is a protein and does not contain RNA has recently been discovered, RNase PhyM is sequence specific for single-stranded RNAs. It cleaves 3-end of unpaired A and U residues, EC3.1.27.3, RNase T1 is sequence specific for single-stranded RNAs. It cleaves 3-end of unpaired G residues, EC3.1.27.1, RNase T2 is sequence specific for single-stranded RNAs. It cleaves 3-end of all 4 residues, but preferentially 3-end of As, EC3.1.27.4, RNase U2 is sequence specific for single-stranded RNAs. It cleaves 3-end of unpaired A residues, EC3.1.27.8, RNase V is specific for polyadenine and polyuridine RNA
32.
Brain
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The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is located in the head, usually close to the organs for senses such as vision. The brain is the most complex organ in a vertebrates body, in a human, the cerebral cortex contains approximately 15–33 billion neurons, each connected by synapses to several thousand other neurons. Physiologically, the function of the brain is to exert centralized control over the other organs of the body, the brain acts on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment, the operations of individual brain cells are now understood in considerable detail but the way they cooperate in ensembles of millions is yet to be solved. This article compares the properties of brains across the range of animal species. It deals with the human brain insofar as it shares the properties of other brains, the ways in which the human brain differs from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because more can be said about them in a human context. The most important is brain disease and the effects of brain damage, the shape and size of the brain varies greatly between species, and identifying common features is often difficult. Nevertheless, there are a number of principles of architecture that apply across a wide range of species. Some aspects of structure are common to almost the entire range of animal species, others distinguish advanced brains from more primitive ones. The simplest way to gain information about brain anatomy is by visual inspection, Brain tissue in its natural state is too soft to work with, but it can be hardened by immersion in alcohol or other fixatives, and then sliced apart for examination of the interior. Visually, the interior of the consists of areas of so-called grey matter, with a dark color, separated by areas of white matter. Further information can be gained by staining slices of tissue with a variety of chemicals that bring out areas where specific types of molecules are present in high concentrations. It is also possible to examine the microstructure of brain tissue using a microscope, the brains of all species are composed primarily of two broad classes of cells, neurons and glial cells. Glial cells come in types, and perform a number of critical functions, including structural support, metabolic support, insulation. Neurons, however, are considered the most important cells in the brain. The property that makes neurons unique is their ability to send signals to target cells over long distances
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Neuromuscular junction
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A neuromuscular junction is a chemical synapse formed by the contact between a motor neuron and a muscle fiber. It is at the junction that a motor neuron is able to transmit a signal to the muscle fiber. Muscles require innervation to function—and even just to muscle tone. Calcium ions bind to sensor proteins on synaptic vesicles, triggering vesicle fusion with the cell membrane, nAChRs are ionotropic receptors, meaning they serve as ligand-gated ion channels. The binding of ACh to the receptor can depolarize the muscle fiber, neuromuscular junction diseases can be of genetic and autoimmune origin. The neuromuscular junction differs from chemical synapses between neurons, presynaptic motor axons stop 30 nanometers from the sarcolemma, the cell membrane of a muscle cell. This 30-nanometer space forms the synaptic cleft through which signalling molecules are released, the sarcolemma has invaginations called postjunctional folds, which increase the surface area of the membrane exposed to the synaptic cleft. These postjunctional folds form what is referred to as the motor endplate, the presynaptic axons form bulges called terminal boutons that project into the postjunctional folds of the sarcolemma. The presynaptic terminals have active zones that contain vesicles, also called quanta and these vesicles can fuse with the presynaptic membrane and release ACh molecules into the synaptic cleft via exocytosis after depolarization. AChRs are localized opposite the presynaptic terminals by protein scaffolds at the postjunctional folds of the sarcolemma, dystrophin, a structural protein, connects the sarcomere, sarcolemma, and extracellular matrix components. Rapsyn is another protein that docks AChRs and structural proteins to the cytoskeleton, also present is the receptor tyrosine kinase protein MuSK, a signaling protein involved in the development of the neuromuscular junction, which is also held in place by rapsyn. The neuromuscular junction is where a neuron activates a muscle to contract and this influx of Ca2+ causes neurotransmitter-containing vesicles to dock and fuse to the presynaptic neurons cell membrane through SNARE proteins. Fusion of the membrane with the presynaptic cell membrane results in the emptying of the vesicles contents into the synaptic cleft. Acetylcholine diffuses into the cleft and can bind to the nicotinic acetylcholine receptors on the motor endplate. Acetylcholine is a neurotransmitter synthesized from choline and acetyl-CoA, and is involved in the stimulation of muscle tissue in vertebrates as well as in some invertebrate animals. In vertebrate animals, the receptor subtype that is found at the neuromuscular junction of skeletal muscles is the nicotinic acetylcholine receptor. Each subunit of this receptor has a characteristic “cys-loop, ” which is composed of a cysteine residue followed by 13 amino acid residues, the two cysteine residues form a disulfide linkage which results in the “cys-loop” receptor that is capable of binding acetylcholine and other ligands. These cys-loop receptors are only in eukaryotes, but prokaryotes possess ACh receptors with similar properties
34.
Sciatic nerve
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The sciatic nerve is a large nerve in humans and other animals. It begins in the back and runs through the buttock. It is the longest and widest single nerve in the human body, the sciatic nerve provides the connection to the nervous system for nearly the whole of the skin of the leg, the muscles of the back of the thigh, and those of the leg and foot. It is derived from spinal nerves L4 to S3 and it contains fibers from both the anterior and posterior divisions of the lumbosacral plexus. The sciatic nerve is formed from the L4 to S3 segments of the sacral plexus, the fibres unite to form a single nerve in front of the piriformis muscle. The nerve passes beneath piriformis and through the greater sciatic foramen, from here, it travels down the posterior thigh to the popliteal fossa. The nerve travels in the compartment of the thigh behind the adductor magnus muscle. The sciatic nerve supplies sensation to the skin of the foot, sensation to skin to the sole of the foot is provided by the tibial nerve, and the lower leg and upper surface of the foot via the common fibular nerve. The sciatic nerve also innervates muscles, in particular, Via the tibial nerve, the muscles in the posterior compartment of the leg and sole of the foot. Via the common peroneal nerve, the muscles in the anterior, pain caused by a compression or irritation of the sciatic nerve by a problem in the lower back is called sciatica. Common causes of sciatica include the lower back and hip conditions, spinal disc herniation, degenerative disc disease, lumbar spinal stenosis, spondylolisthesis. Other acute causes of sciatica include coughing, muscular hypertension, sciatic nerve injury occurs between 0. 5% and 2. 0% of the time during total hip arthroplasty. Sciatic nerve palsy is a complication of total hip arthroplasty with an incidence of 0. 2% to 2. 8% of the time, the nerve can be surrounded in oxidized regenerated cellulose to prevent further scarring. Sciatic nerve palsy can also result from spinal stenosis following the procedure. It is unclear if inversion therapy is able to decompress the sacral vertebrae, sciatic nerve exploration can be done by endoscopy in a minimally invasive procedure to assess lesions of the nerve. According to Jewish law, the nerve cannot be eaten
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Sartorius muscle
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The sartorius muscle is the longest muscle in the human body. It is a long, thin, superficial muscle that runs down the length of the thigh in the anterior compartment, the sartorius muscle originates from the anterior superior iliac spine and part of the notch between the anterior superior iliac spine and anterior inferior iliac spine. It runs obliquely across the upper and anterior part of the thigh in an inferomedial direction and it passes behind the medial condyle of the femur to end in a tendon. This tendon curves anteriorly to join the tendons of the gracilis and semitendinosus muscles in the pes anserinus and its upper portion forms the lateral border of the femoral triangle, and the point where it crosses adductor longus marks the apex of the triangle. Deep to sartorius and its fascia is the canal, through which the saphenous nerve, femoral artery and vein. Like the other muscles in the compartment of the thigh. It may originate from the end of the inguinal ligament, the notch of the ilium. The muscle may be split into two parts, and one part may be inserted into the fascia lata, the femur, the tendon of insertion may end in the fascia lata, the capsule of the knee-joint, or the fascia of the leg. The muscle may be absent in some people, the sartorius muscle can move the hip joint and the knee joint, but all of its actions are weak, making it a synergist muscle. At the hip, it can flex, weakly abduct, at the knee, it can flex the leg, when the knee is flexed, sartorius medially rotates the leg. Turning the foot to look at the sole or sitting cross-legged demonstrates all four actions of the sartorius, one of the many conditions that can disrupt the use of the sartorius is pes anserine bursitis, an inflammatory condition of the medial portion of the knee. This condition usually occurs in athletes from overuse and is characterized by pain, swelling, the pes anserinus is made up from the tendons of the gracilis, semitendinosus, and sartorius muscles, these tendons attach onto the anteromedial proximal tibia. When inflammation of the underlying the tendons occurs they separate from the head of the tibia. Sartorius comes from the Latin word sartor, meaning tailor, there are four hypotheses as to the genesis of the name. One is that name was chosen in reference to the cross-legged position in which tailors once sat. Another is that it refers to the location of the portion of the muscle being the inseam or area of the inner thigh that tailors commonly measure when fitting trousers. A third is that the muscle closely resembles a tailors ribbon, additionally, antique sewing machines required continuous cross body pedaling. This combination of rotation and flexion of the hip and flexion of the knee gave tailors particularly enlarged sartorius muscles
36.
In vitro
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In vitro studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. In contrast, in studies are those conducted in animals, including humans. In vitro studies are conducted using components of an organism that have been isolated from their biological surroundings, such as microorganisms, cells. For example, microrganisms or cells can be studied in artificial culture media, colloquially called test-tube experiments, these studies in biology, medicine, and their subdisciplines are traditionally done in test tubes, flasks, Petri dishes, etc. They now involve the range of techniques used in molecular biology. In contrast, studies conducted in living beings are called in vivo, polymerase chain reaction is a method for selective replication of specific DNA and RNA sequences in the test tube. Protein purification involves the isolation of a protein of interest from a complex mixture of proteins. In vitro fertilization is used to allow spermatozoa to fertilize eggs in a culture dish before implanting the resulting embryo or embryos into the uterus of the prospective mother and these ADME process parameters can then be integrated into so called physiologically based pharmacokinetic models or PBPK. In vitro studies permit a species-specific, simpler, more convenient, just as studies in whole animals more and more replace human trials, so are in vitro studies replacing studies in whole animals. This complexity makes it difficult to identify the interactions between individual components and to explore their basic biological functions, in vitro work simplifies the system under study, so the investigator can focus on a small number of components. Another advantage of in vitro methods is that cells can be studied without extrapolation from an experimental animals cellular response. Investigators doing in vitro work must be careful to avoid over-interpretation of their results, for example, scientists developing a new viral drug to treat an infection with a pathogenic virus may find that a candidate drug functions to prevent viral replication in an in vitro setting. However, before this drug is used in the clinic, it must progress through a series of in vivo trials to determine if it is safe and effective in intact organisms. Results obtained from in vitro experiments cannot usually be transposed, as is, building a consistent and reliable extrapolation procedure from in vitro results to in vivo is therefore extremely important. However, increasingly sophisticated in vitro experiments collect increasingly numerous, complex, mathematical models, such as systems biology models, are much needed here. In pharmacology, IVIVE can be used to approximate pharmacokinetics or pharmacodynamics and that indicates that extrapolating effects observed in vitro needs a quantitative model of in vivo PK. Physiologically based PK models are generally accepted to be central to the extrapolations, in these conditions, developing a simple PD model of the dose–response relationship observed in vitro, and transposing it without changes to predict in vivo effects is not enough
37.
Biomechanics
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Biomechanics is the study of the structure and function of biological systems such as humans, animals, plants, organs, fungi, and cells by means of the methods of mechanics. Biomechanics is closely related to engineering, because it often uses traditional engineering sciences to analyze biological systems, some simple applications of Newtonian mechanics and/or materials sciences can supply correct approximations to the mechanics of many biological systems. Usually biological systems are more complex than man-built systems. Numerical methods are applied in almost every biomechanical study. Research is done in a process of hypothesis and verification, including several steps of modeling, computer simulation. Elements of mechanical engineering, electrical engineering, computer science, gait analysis, Biomechanics in sports can be stated as the muscular, joint and skeletal actions of the body during the execution of a given task, skill and/or technique. Proper understanding of biomechanics relating to sports skill has the greatest implications on, sports performance, rehabilitation and injury prevention, as noted by Doctor Michael Yessis, one could say that best athlete is the one that executes his or her skill the best. The mechanical analysis of biomaterials and biofluids is usually carried forth with the concepts of continuum mechanics and this assumption breaks down when the length scales of interest approach the order of the micro structural details of the material. One of the most remarkable characteristic of biomaterials is their hierarchical structure, in other words, the mechanical characteristics of these materials rely on physical phenomena occurring in multiple levels, from the molecular all the way up to the tissue and organ levels. Biomaterials are classified in two groups, hard and soft tissues, mechanical deformation of hard tissues may be analysed with the theory of linear elasticity. On the other hand, soft tissues usually undergo large deformations and thus their analysis rely on the strain theory. The interest in continuum biomechanics is spurred by the need for realism in the development of medical simulation, biological fluid mechanics, or biofluid mechanics, is the study of both gas and liquid fluid flows in or around biological organisms. An often studied liquid biofluids problem is that of blood flow in the cardiovascular system. Under certain mathematical circumstances, blood flow can be modelled by the Navier–Stokes equations, in vivo whole blood is assumed to be an incompressible Newtonian fluid. However, this fails when considering forward flow within arterioles. At the microscopic scale, the effects of red blood cells become significant. When the diameter of the vessel is just slightly larger than the diameter of the red blood cell the Fahraeus–Lindquist effect occurs. However, as the diameter of the vessel decreases further
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Jumping
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Jumping or leaping is a form of locomotion or movement in which an organism or non-living mechanical system propels itself through the air along a ballistic trajectory. Some animals, such as the kangaroo, employ jumping as their form of locomotion, while others, such as frogs. Jumping is also a key feature of various activities and sports, including the long jump, high jump, all jumping involves the application of force against a substrate, which in turn generates a reactive force that propels the jumper away from the substrate. Any solid or liquid capable of producing a force can serve as a substrate. Examples of the latter include dolphins performing traveling jumps, and Indian skitter frogs executing standing jumps from water, jumping organisms are rarely subject to significant aerodynamic forces and, as a result, their jumps are governed by the basic physical laws of ballistic trajectories. Consequently, while a bird may jump into the air to initiate flight, no movement it performs once airborne is considered jumping, following the moment of launch, a jumper will traverse a parabolic path. The launch angle and initial launch velocity determine the distance, duration. The maximum possible horizontal travel distance occurs at a angle of 45 degrees. Muscles do physical work, adding energy to the jumpers body over the course of a jumps propulsive phase. This results in a kinetic energy at launch that is proportional to the square of the jumpers speed, the more work the muscles do, the greater the launch velocity and thus the greater the acceleration and the shorter the time interval of the jumps propulsive phase. Mechanical power and the distance over which that power is applied are the key determinants of jump distance, as a result, many jumping animals have long legs and muscles that are optimized for maximal power according to the force-velocity relationship of muscles. The maximum power output of muscles is limited, however, to circumvent this limitation, many jumping species slowly pre-stretch elastic elements, such as tendons or apodemes, to store work as strain energy. Such elastic elements can release energy at a higher rate than equivalent muscle mass. A jumper may be stationary or moving when initiating a jump. In a jump from stationary, all of the required to accelerate the body through launch is done in a single movement. In a moving jump or running jump, the jumper introduces additional vertical velocity at launch while conserving as much momentum as possible. Consequently, jumpers are able to jump greater distances when starting from a run, animals use a wide variety of anatomical adaptations for jumping. Aquatic species rarely display any particular specializations for jumping and those that are good jumpers usually are primarily adapted for speed, and execute moving jumps by simply swimming to the surface at a high velocity
39.
Aquatic locomotion
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Aquatic locomotion is biologically propelled motion through a liquid medium. The simplest propulsive systems are composed of cilia and flagella, Swimming has evolved a number of times in a range of organisms including arthropods, fish, molluscs, reptiles, birds, and mammals. Swimming evolved a number of times in unrelated lineages, and the evolutionary pressures leading to its adoption are unknown, supposed jellyfish fossils occur in the Ediacaran, but the first free-swimming animals appear in the Early to Middle Cambrian. These are mostly related to the arthropods, and include the Anomalocaridids, cephalopods joined the ranks of the nekton in the late Cambrian, and chordates were probably swimming from the Early Cambrian. Many terrestrial animals retain some capacity to swim, however some have returned to the water, ciliates use small flagella called cilia to move through the water. One ciliate will generally have hundreds to thousands of cilia that are packed together in arrays. During movement, an individual cilium deforms using a power stroke followed by a low-friction recovery stroke. Since there are multiple cilia packed together on an individual organism and this means the deformation of one cilium is in phase with the deformation of its neighbor, causing deformation waves that propagate along the surface of the organism. These propagating waves of cilia are what allow the organism to use the cilia in a manner to move. A typical example of a ciliated microorganism is the Paramecium, a one-celled, ciliated protozoan covered by thousands of cilia, the cilia beating together allow the Paramecium to propel through the water at speeds of 500 micrometers per second. Certain organisms such as bacteria and animal sperm have flagellum which have developed a way to move in liquid environments, a rotary motor model shows that bacteria uses the protons of an electrochemical gradient in order to move their flagella. Torque in the flagella of bacteria is created by particles that conduct protons around the base of the flagellum, the direction of rotation of the flagella in bacteria comes from the occupancy of the proton channels along the perimeter of the flagellar motor. Movement of sperm is called sperm motility, the middle of the mammalian spermatozoon contains mitochondria that power the movement of the flagellum of the sperm. The motor around the base produces torque, just like in bacteria for movement through the aqueous environment, movement using a pseudopod is accomplished through increases in pressure at one point on the cell membrane. This pressure increase is the result of actin polymerization between the cortex and the membrane, as the pressure increases the cell membrane is pushed outward creating the pseudopod. When the pseudopod moves outward, the rest of the body is pulled forward by cortical tension, the result is cell movement through the fluid medium. Furthermore, the direction of movement is determined by chemotaxis, when chemoattraction occurs in a particular area of the cell membrane, actin polymerization can begin and move the cell in that direction. An excellent example of an organism that utilizes pseudopods is Naegleria fowleri, a Simple Animation Among the radiata, jellyfish and their kin, the main form of swimming is to flex their cup shaped bodies
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. PMID 14946732.
